A spark plug having a connection portion disposed between a metal terminal and a center electrode. The connection portion includes: a magnetic substance formed from a Fe-containing oxide; a conductor which is a wire helically disposed on an outer periphery of the magnetic substance and electrically connected to the metal terminal and the center electrode; and an intermediate member which is in contact with the magnetic substance, the conductor, and an inner peripheral surface of the insulator, is disposed between the magnetic substance and the conductor, and the inner peripheral surface of the insulator, and has lower electrical conductivity than the conductor. The conductor is made of one or more of an oxide conductor, carbon, and a carbon compound.